Case for nuclear light source material



May 29, 1962 s. G. BARTOLOMEI CASE FOR NUCLEAR LIGHT SOURCE MATERIAL Filed Oct. 29, 1957 b INVENTOR.

Gea'l9c Gjmblom W ATTORNEY "Fig.5

United States atent Otifice 3,037,067 Patented May 29, 1962 3,037,067 CASE FOR NUCLEAR LIGHT SOURCE MATERIAL George G. Bartolomei, Bayville, N.Y., assignor to Associated Nucleonics, Inc., a corporation of New York Filed Oct. 29, 1957, Ser. No. 693,165 6 Claims. (Cl. 13689) The present invention relates to an energy source device of the type wherein nuclear energy first is converted to light and the light is then converted to electrical energy, and, more particularly, to an improved case for nuclear light source material of such a device.

In such devices, a radioactive material, a phosphor and a photoelectric cell are arranged so that light is emitted by the phosphor in response to disintegration of the radioactive material and the light is converted to electrical energy by the cell. This may be accomplished by confining thin layers of phosphor and radioactive material or a single layer of a mixture of such materials in a relatively shallow chamber of about five-thousandths of an inch. The primary requirement has been to provide an entirely enclosed, uniform layer of such materials.

The method presently employed in producing nuclear light source devices comprises placing a quantity of material into a shallow cup-shaped container, levelling off the material, putting a cover in place, and sealing the contacting edges of the cover and the container with cement. Because these operations are presently performed with gloved hands in a shielded confined area, the operations are very difficult to carry out and the finished product is far from satisfactory.

Accordingly, an object of the present invention is to provide a case for nuclear light source material which is not subject to the foregoing difiiculties and disadvantages.

Another object is to provide such a case wherein the chamber is dimensioned to provide a layer of uniform thickness upon introducing therein a given quantity of material.

Another object is to provide such a case which can be sealed in a manner to reduce the leakage hazard to a minimum and can be tested for leakage prior to filling the same.

Another object is to provide such a case, which facilitates mounting photoelectric cells thereon.

Another object is to provide such a case which is adapted for automatic loading.

Another object is to provide such a case which can be produced in various sizes and shapes.

A further object is to accomplish the foregoing in a simple, practical and economical manner.

Other and further objects of the invention will be obvious upon an understanding of the illustrative embodiment about to be described, or will be indicated in the appended claims, and various advantages not referred to herein will appear to one skilled in the art upon employment of the invention in practice.

In the drawing:

FIG. 1 is an enlarged plan view of a case in accordance with the present invention.

FIG. 2 is a sectional view taken along the line 2-2 on FIG. 1.

FIG. 3 is a sectional view taken along the line 3-3 on FIG. 1.

FIGS. 4 and 5 are sectional views similar to FIG. 2 illustrating modified embodiments of the present invention.

Referring to the drawing in detail, there is shown a light source device which includes a case having a shallow internal chamber 11 provided with an opening 12 extending to the exterior of the case for introducing light source material 13 into the chamber. Preferably,

the case has internal recess means 14 which extends diametrically from the opening to within the chamber to facilitate even distribution of the light source material in the chamber. After the chamber has been filled, the opening 12 is sealed by means of a plug 15.

As illustrated herein, the case preferably comprises a pair of circular disc-like members and 10b which have cooperating formations to provide the chamber 11, the opening 12 and the recess means 14.

In order to simplify the construction of the case and reduce its cost to a minimum, the case members are identical in construction and have complementary formations which provide the internal structure thereof.

The case members are constructed of transparent material through which light radiations ranging from the near infra-red to the ultra-violet in the spectrum can be transmitted, for example, polystyrene or polymerized methyl methacrylate type resins.

Such materials enable the case members to be arranged, as shown, and heat sealed at the periphery thereof to provide a leak-proof chamber. The effectiveness of the seal so provided can be tested prior to filling the chamber, whereby defective cases can be rejected and reprocessed to make an effective heat seal. The plug 15 is constructed of the same material as the case members and can be heat sealed into the opening 12 to confine the light source material in a leak-proof manner. If desired, the case members and the plug can be adhesively secured, but heat scaling is preferred because it pro vides an autogenous indestructible bond between these parts.

The light source material 13 with which the chamber is filled may be a mixture of nuclear source or radioactive material and a phosphor, for example, Pm O and zinc sulphide in admixture as a finely divided powder.

The case shown in FIGS. 1, 2 and 3 is further provided with a pair of semi-circular recesses 16 on the outer faces of the case members adapted to have photoelectric cells 9 fitted and secured therein to overlie the chamber (FIG. 2). A rib 17 divides each pair of these recesses and provides structure in which arcuate diametrically extending recesses 18 can be formed at the inner faces of the case members, whereby the recess means 14 is, in efiect, a circular bore which extends from the opening 12 and through the chamber.

This bore enables the light source powder to be evenly distributed within the chamber. As can be seen, the chamber is provided by circular recesses 19 on the inner faces of the case members, and an annular flat zone 20 surrounds each circular recess which facilitates heat sealmg.

Since the case is shown in FIGS. 1, 2 and 3 as enlarged ten times, reference to its approximate dimensions will enable a better understanding of its actual size.

Case member diameter inch 0.540 Case member overall thickness do .050 Recess 16 radius do .255 Recess 16 depth do .037 Bore 14 and opening 12 diameter do .020 Plug 15 diameter do .021 Recess 19 diameter do .045 Recess 19 depth do .003 Wall thickness between recesses 16 and 19 do .010 Chamber thickness do .006 Chamber capacity cu. in .001

In FIG. 4, another form of case is shown which comprises a pair of members 10:: and 101) which have a substantially uniform wall thickness throughout and are formed with chamber providing recesses 19 and recesses 18 on their inner faces. Flat annular peripheral Zones 20 are heat sealed to each other. ing dimensions:

This case has the follow- In FIG. 5, a somewhat larger and more rugged case is shown wherein the case members 10a and 10b are fiat discs formed With internal recesses 18 and 19. This case has the following dimensions:

Case member diameter "inch" 1.750 Case member thickness do .130 Bore 14 and opening 12 diameter do .024 Recess 19 diameter dou 1.260 Recess 19 depth do .003 Chamber thickness do .006 Chamber capacity cu. in .007

An important advantage of the cases just described is that they can be filled in a more simple, rapid and economical manner with minimum health hazards. This is accomplished by placing the empty case with the opening 12 up, in a holding fixture having an open bottom seat for the cup of a hypodermic needle which is arranged so that the lower end of the needle extends into the opening 12. The holding fixture is placed on a vibrator within a shielded zone, and a measured quantity of light source powder is placed into the needle cup. The holding fixture and the case are vibrated to cause the material to leave the cup and flow into the chamber of the case. Visual observation indicates the completion of the filling operation. The case is then removed from the fixture, and the opening 12 is sealed oil by applying a plug of heat softened resin, which upon cooling is heat-seal bonded within the opening. The sealed case containing the light source material can then be safely removed from the shielded zone.

The case shown in FIGS. 1 and 2 is primarily adapted to be used in a nuclear battery because semi-circular cells 9, such as silicon photocells shown in broken lines herein. can be sealed in the recesses 16 with their light sensitive side facing the transparent upper and lower Walls of the chamber 11 and with their terminals at the opposite side exposed exteriorly of the recesses 16 for connection in a parallel or series circuit (not shown).

The cases shown in FIGS. 4 and 5 also can be used in a nuclear battery by mounting photocells (not shown) on the transparent upper and lower walls of the chamber 11, but their simplified form enables the same to be used solely as a light source for flash light" or warning light having a long life.

From the foregoing description, it will be seen that the present invention provides an improved case for a light source device or a nuclear battery having fully controllable external and internal physical dimensions, having adaptability for automatic or semiautomatic filling. All these advantages are attained with maximum economy.

As various changes may be made in the form, construction and arrangement of the parts herein, without departing from the spirit and scope of the invention and without sacrificing any of its advantages, it is to be understood that all mattcr herein is to be interpreted as illustrative and not in any limiting sense.

I claim:

1. A case for nuclear light source material constructed, at least in part, of material through which light radiations ranging from the near infra-red to the ultra-violet in the spectrum can be transmitted, said case comprising a shallow internal chamber of substantially equal depth throughout most of the chamber, an opening extending from the side of said chamber to the exterior of the case, and an internal channel of greater depth than the chamher, said channel being in communication with said opening and extending into the chamber a substantial distance to facilitate loading thereof.

2. A case according to claim 1, having an external recess overlying said chamber for receiving a photoelectric cell.

3. A case according to claim 1, wherein said internal channel extends from said opening substantially the full distance of the chamber to a wall thereof diametrically opposed to said opening.

4. A case according to claim 1 wherein the case is constructed of a material through which light radiations ranging from the visible to the ultra-violet in the spectrum can be transmitted.

5. In a nuclear battery, a case constructed of two disclike members sealed together and being formed of material through which light radiations ranging from the near infrared to the ultra-violet in the spectrum can be transmitted, said case members providing a shallow internal chamber being of substantially equal depth throughout most of the chamber formed with an opening at the peripheral edge thereof extending to the exterior of said case, photoelectric cell means mounted on and secured to said case members to overlie said chamber, a mass of nuclear light source material in said chamber, and sealing means for said opening to confine said material.

6. In a nuclear battery, a case constructed of two disclike members sealed together and being formed of material through which light radiations ranging from the near infra-red to the ultra-violet in the spectrum can be transmitted, said case members providing a shallow internal chamber formed with an opening at the peripheral edge thereof extending to the exterior of said case and said case members having external recess means overlying said chamber, photoelectric cell means fitted and secured in said recess means, a mass of nuclear light source material in said chamber, and sealing means for said opening.

References Cited in the file of this patent UNITED STATES PATENTS 2,313,766 Pfanstiehl Mar. 16, l943 2,479,882 Wallhausen et al Aug. 23, 1949 2,575,134 Schultz et al Nov. 13, 1951 2,857,524 Tabern Oct. 21, 1958 FOREIGN PATENTS 638,106 Great Britain May 31, 1950 OTHER REFERENCES Elgin-Kidde Nuclear Battery; Radio-Electronics; April 1957; page 47. 

